Analytical sensors, e.g., test strips, are commonly used to determine the presence and concentration of an analyte in biological fluid. Such sensors may be used, for example, to monitor blood glucose levels of diabetic patients.
In using analyte sensors, an opening is created in the skin (e.g., by lancing the skin) to cause a flow of biological fluid from the region. At least a portion of this biological fluid is contacted to a sensor where the concentration of analyte in the fluid is then determined. Specifically, an opening in the skin is produced and an opening (i.e., a sample port) of the sensor is contacted to the expressed biological fluid to bring the fluid into contact with the sample chamber of the sensor where analysis occurs. The sample chamber is in fluid communication with the sample port.
Locating the sample port and contacting it with biological fluid is not without difficulty and becomes an even greater concern as the size of sample chambers are decreased to, e.g., decrease sample volumes, decrease test time, etc. Sample ports of conventional sensors are located on the top (“top fill”), the centered front end (“front-fill”), or a side (“side fill”) of the sensors, which makes it difficult for a user to locate and contact with biological fluid. Users of such devices may have visual and/or dexterity problems, e.g., resulting from an underlying disease state such as diabetes, further compounding the difficulty in locating the sample port and positioning near a site of biological fluid.
The inability to easily locate the sample port and properly contact the sample to be tested with the sample port may not simply be a minor nuisance, but may have serious consequences. For example, in attempts to locate the sample port, the sample maybe smeared over the sensor surfaces resulting a difficult to handle sensor.
Sample smearing, and other factors associated with the inability to easily locate the sample port may have other serious consequences as well. For example, such may deplete the volume of sample available for testing so there may not be a sufficient amount of sample. A test may not begin and/or erroneous testing results may occur if an insufficient sample volume is present in the sample chamber. Insufficient sample volumes in the sample chamber may require the user to either “milk” the originally lanced site in an attempt to obtain more sample from the site or to lance an additional site. The user may associate both options with significant pain and may therefore elect instead to forego the testing. Foregoing testing may have serious health implications, e.g., it is desirable for a diabetic to test glucose levels multiple times throughout the day to sufficiently manage the diabetes.
Attempts have been made to address the above-described issues. For example, a test strip having cone-shaped channel entrance in the center of the front end of the test strip has been developed, but has not adequately addressed the problems and adds complexity to the manufacturing process.
Accordingly, as analyte sensors continue to be of importance in health management, there continues to be an interest in devices and methods that make testing easier, including testing devices and methods that enable a user to easily contact an analyte-containing sample with the sample chamber of the sensor. Of particular interest are analyte sensors and analyte testing methods that are easy and cost effective to manufacture and are easy to use, particularly for visually and/or dextrally impaired users.